Transition from high-entropy to conventional (TiZrNbCu)1-xCox metallic glasses
Abstract
A new amorphous alloy system (TiZrNbCu)1-xCox covering a broad composition range from the high-entropy (HEA) to Co rich alloys (x≤slant 0.43) has been fabricated, characterized and investigated. A comprehensive study of the chemical compositions, homogeneity, thermal stability, electronic structure and magnetic and mechanical properties has been performed. All properties change their variations with x within the HEA range. In particular, the average atomic volume deviates from the Vegard's law for x 0.2, where also the average atomic packing fraction suddenly changes. The valence band structure, studied with ultraviolet photoemission spectroscopy, shows a split-band shape with 3d-states of Co approaching the Fermi level on increasing x. Due to onset of magnetic correlations magnetic susceptibility rapidly increases for x 0.25. Very high microhardness increases rapidly with x. The results are compared with those for similar binary and quinary metallic glasses and with those for Cantor type of crystalline alloys.